Four point restraint apparatus

ABSTRACT

A four point restraint apparatus for a vehicle includes in a preferred embodiment a first pair of flexible lap belts connected at laterally opposite sides of a seat cushion with inner ends transversely connectable to one another across pelvic regions of an occupant and a second pair of flexible shoulder belts connected to a support in the vehicle body and extending forward of the seat back adjacent the neck and across the clavicle of the occupant. The shoulder belts extend from the clavicle essentially parallel downward across front edge portions of the occupant&#39;s rib cage to laterally spaced attachment with the lap belts adjacent pelvic regions of an occupant. Additional features of the preferred apparatus include a ramp sloping upward toward a forward edge of the cushion; an upwardly adjustable load-carrying headrest in the seat back for guiding the shoulder belts over the clavicle of an occupant; a load-limiting retractor or laterally spaced dual load-limiting retractors connecting the shoulder belts to the seat back; one or more dynamic pretensioners connected with the lap belts; and maintaining the spacing of the shoulder belts at a constant approximately 62.5 mm lateral offset in opposite directions from a center of the occupant&#39;s position over a distance from the clavicle of the occupant to connection with the lap belts.

TECHNICAL FIELD

This invention relates to apparatus for restraining an occupant in anautomotive vehicle seat during rapid deceleration. More particularly,the invention relates to a four point restraint apparatus.

BACKGROUND OF THE INVENTION

It is known in the automotive vehicle art to provide various types ofseat belts or restraint apparatus for restraining an occupant in theseat and providing controlled deceleration of portions of the body tolimit the forces applied to the occupant's body during rapiddeceleration of a vehicle from a cause such as a collision. Four pointrestraint apparatus are among the many types provided for use in varioustypes of vehicles.

SUMMARY OF THE INVENTION

The present invention provides a four point restraint apparatus designedto reduce and distribute forces applied to the body of an occupantduring rapid deceleration conditions. As used herein, the term “cushion”conventionally refers to the body supporting lower portion of a seatand, in particular, to the structural cushion frame assembly to whichcushion materials are typically attached. The term “seat back” similarlyrefers to a back supporting portion and, particularly, to the structuralseat back frame which is connected to the cushion and to which cushionmaterials are typically also attached.

In a preferred form, an apparatus according to the invention includes:

a seat having a cushion mountable on a vehicle underbody and a seat backconnected with the cushion;

a first pair of flexible lap belts connected at laterally opposite sidesof the seat through at least one dynamic pretensioner and having innerends transversely connectable to one another across pelvic regions ofthe occupant;

a second pair of flexible shoulder belts connected to a support in thebody through at least one load-limiting retractor and, when in use,extending in parallel relation forward of the seat back, passing closelyadjacent the neck portion and across the clavicle of the occupant frompoints not below the level of the clavicle, the shoulder beltsextending, essentially parallel, downward across front edge portions ofthe occupant's rib cage to laterally-spaced attachment with said lapbelts; and

adjustable guides on the seat back for guiding the shoulder belts overthe clavicle to limit downward force on the clavicle prior to anoccurrence of rapid vehicle deceleration. preferably, the shoulder beltsare connected to a fixed support in the vehicle body spaced and directlycentered behind the back portion of the seat; however, they couldinstead be connected to another suitable location on the body or on theseat.

Additional features included in the apparatus are:

the load-limiting retractor, or laterally-spaced dual load-limitingretractors, connecting the shoulder belts to the support to allowcontrolled extension of the shoulder belts upon reaching a predetermineddeceleration load;

preferably, dual pretension retractors, mounted on laterally oppositesides of the seat and connected with the lap belts to provide dynamicpretensioning of the lap belts upon reaching a predetermineddeceleration value;

a ramp sloping upward near the forward edge of the seat cushion andbeing effective to prevent sliding of the body of an occupant forwardunder the transversely-connected lap belts during rapid slowing of thevehicle;

an upwardly adjustable load carrying headrest on the seat back providingthe adjustable guides for guiding the shoulder belts over the clavicleof an occupant; and

maintaining the spacing of the shoulder belts at a constantapproximately 62.5 mm lateral offset in opposite directions from acenterline through the position of the occupant over a distance from theclavicle of the occupant to laterally-spaced attachment to the lap beltsadjacent pelvic regions of the occupant.

These and other features and advantages of the invention will be morefully understood from the following description of certain specificembodiments of the invention taken together with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a fragmentary pictorial view of a vehicle restraint apparatusincorporating a seat with a four point restraint apparatus according tothe invention;

FIG. 2 is a view similar to FIG. 1 showing a second embodiment of theinvention;

FIG. 3 is a side view of the embodiment of FIG. 2 but showing the lapand shoulder belts in a retracted position;

FIG. 4 is a pictorial view showing the embodiment of FIG. 2 in use in avehicle;

FIG. 5 is a front elevational view illustrating shoulder belts guided byrollers in an adjustable headrest;

FIG. 6 is a partial front elevational view of the seat cushion showingthe anti-submarining ramp;

FIG. 7 is a pictorial view illustrating one form of belt attachmenthardware;

FIG. 8 is a pictorial view illustrating a preferred form of beltattachment hardware;

FIG. 9 is a side view showing a first form of lap belt pretensioner;

FIG. 10 is a pictorial view illustrating a lap belt retractorpretensioner application;

FIG. 11 is a rear view showing application of a centrally mountedretractor pretensioner;

FIG. 12 is a rear view similar to FIG. 11 showing a hypertensioner inplace of the pretensioner; and

FIG. 13 is a side view illustrating a lap belt anchor roller bearing foruse with the embodiments of FIGS. 11 and 12.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring first to FIGS. 1-6 of the drawings, there are shown twosimilar embodiments of the application of four point restraint apparatusaccording to the invention. Two different embodiments of the restraintapparatus applying four point restraints are shown by numeral 10 in FIG.1 and numeral 12 in FIG. 2.

Each apparatus 10, 12 includes a vehicle body 14 having an underbody 16and a transverse rear bulkhead or other vehicle structure defining afixed support 18. A seat 20 is included having a cushion 22 and a seatback 24, referring in particular to their underlying structural frameassemblies. Preferably, an adjustable headrest 26 is also provided whichis mounted on vertically adjustable headrest supports 28 that areadjustably connected with lateral cross members 30, 32 in the seat back.

The cushion 22 of the seat 20 is conventionally mounted on the underbody16, preferably on structural seat adjusters 34, located along thebottoms of the sides of the seat, which allow forward and aft adjustmentof the seat on the underbody. The cushion 22 of the seat includes ananti- submarining ramp 36 having a surface sloping upward near theforward edge of the cushion. The underlying portions of the seatstructure, which are shown and referred to in the figures, areconventionally covered by suitable materials for comfortably seating theoccupant and providing cushion to the occupant's body. These coveringmaterials are shown in phantom in some of the drawings so that theunderlying seat structure may be more clearly illustrated.

The four point restraint apparatus 10, 12 further includes a first pairof flexible belts 38, 40, commonly called seat belts or lap belts. Lapbelts 38, 40 have outer ends 42 connected to laterally opposite sides ofthe structural seat adjusters 34. The outer ends 42 are connected to theseat by some form of pretensioner. In the present instance, dualpretension retractors 44 are used, one connected to each of the belts38, 40. Inner ends 46 of the belts 38, 40 are connectable to one anotherby any suitable means so that, when in use, lap belts 38, 40 extendtransversely across the pelvic regions of the occupant to positivelyrestrain the occupant in the seat during rapid deceleration conditions.

The restraint apparatus additionally includes a second pair of flexibleshoulder belts 48, 50. These shoulder belts are connected at rear endsto the fixed support 18 of the body. Alternatively, they could beconnected to another fixed support in the body or in the associated seatitself. In the apparatus 10 of FIG. 1, the rear ends of the shoulderbelts 48, 50 are joined together and connected to a single load-limitingretractor 52 mounted on the support 18. In the alternative apparatus 12of FIG. 2, the two shoulder belts are connected separately to individualload-limiting retractors 52 mounted on support 18. In both cases, theshoulder belts 48, 50 extend forward to pass through openings or slotsin the associated headrest 26, being guided by bearing rollers 54 whichare mounted in the headrest. The rollers 54 transmit compressive loadsbetween the shoulder belts and adjustable headrest supports 28,connected with the associated seat backs 24, during periods when thebelts are loaded during use. The headrest 26 is adjusted so that thebearing rollers are above, or at least not below, the level of anoccupant's shoulders so as to avoid application of downward forces onthe occupant.

The rollers 54 are set to guide the shoulder belts 48, 50 at an offsetdistance of 62.5 mm more or less from a centerline 55 (FIG. 5), whichrepresents the center of the intended position of an occupant's bodywhen located in the seat. The shoulder belts are thus spaced essentially125 mm apart as they pass over the shoulders or clavicle of an occupantand past the neck portion of the body. The belts 48, 50 then turndownward, remaining parallel and extending across the front edgeportions of the occupant's rib cage and are attached at equallylaterally-spaced locations with the first pair of flexible lap belts 38,40. preferably, the shoulder belt 50 and lap belt 40 on the right sideare attached together at their lower and inner ends and the shoulderbelt 48 and lap belt 38 on the left side are attached together at theirlower and inner ends, and the two sections are connected by a suitablebuckle or buckle and latch assembly 56 which is easily actuated by theoccupant when putting on the restraint apparatus.

FIG. 3 shows in side view the form of the seat 20 and, in particular, apreferred shape for the ramp 36. The lap belt 38 and shoulder belt 48are shown retracted and the long retracted length of the shoulder beltis illustrated.

FIG. 4 illustrates the application of the restraint apparatus in thefront compartment of a vehicle with the driver in position belted inplace in the driver's seat.

FIG. 5 illustrates more clearly the mounting of the headrest 26 on theseat back 24 of the seat with the shoulder belts 48, 50 extendingthrough slots in the headrest and over the associated rollers 54.

FIG. 6 illustrates the front of cushion 22 of the seat and, inparticular, the shape of the ramp 36 at the forward portion of theoccupant's seat area.

Referring now to FIG. 7, there is shown one alternative form ofconnection of the lap belt 38 held in a clinching latch plate 60 withthe shoulder belt 48 in an accompanying stitched latch plate 62 mountedtogether to form a single latch component.

FIG. 8 illustrates a preferred embodiment wherein both the shoulder belt48 and lap belt 38 are stitched to the latch plate 64.

FIG. 9 illustrates one form of pretensioner 66 connected to a stitchedhead 68 for constant attachment with a lap belt 40.

FIG. 10 shows a preferred embodiment wherein the lap belt 40 outer end42 is connected to a non-load limiting pre tensioning retractor 44mounted on a structural seat adjuster 34 near its rear end along thebottom of a side of the seat.

FIG. 11 illustrates still another alternative embodiment wherein anunder seat, centrally-mounted retractor pretensioner 70 is provided toengage the outer ends 42 of lap belts 38, 40 which are drawn throughroller bearing guides 72 at the sides of the seat 20 and extend upwardin otherwise conventional fashion.

FIG. 12 shows still another embodiment wherein a hypertensioner 74 (suchas in U.S. Pat. No. 5,913,486, issued Jun. 22, 1999) is substituted forthe under seat pretensioner 70 of FIG. 11.

FIG. 13 illustrates, in particular, a roller bearing guide 72 having alap belt anchor plate 76 with a roller bearing 78 for guiding the beltfrom the side of the seat to the underneath portion for connection to acentrally-mounted pretensioner or hypertensioner.

In operation of the various embodiments of the restraint apparatus 10,12 described, all of the various components provide important functions.The parallel positioning of the dual shoulder belts 48, 50 properlypositions the belts to provide maximum restraint to the body atpreferred locations. In a preferred embodiment, the shoulder belts areoffset 62.5 mm in opposite directions from a bodily position centerline.This is controlled by guide rollers 54 which guide the belts 48, 50through slots in the headrest or seat back. The shoulder belts arepositioned to pass over the clavicle on the inner shoulder portion ofthe occupant's body closely adjacent the neck in a position wheremaximum restraining force may be applied. The belts 48, 50 then passdown in parallel fashion along the forward edges of the rib cage toconnection with associated lap belts 48, 50. This maintains the desiredpositions of the shoulder belts.

The use of a long shoulder belt length extending from the load limitingretractors 52 to the seat cushion is desired because it allows theshoulder belts to be donned with minimal tension, thereby insuring thatthe buckle starts low on the lap. Upon sufficiently rapid decelerationof the vehicle, the load limiting retractors allow the user's upper bodyto displace forward, minimizing restraint loads. Here, the load-limitingretractors 52 have the function of allowing controlled motion of thebody only when a prescribed load limit is reached, thus maintainingcontrolled forces on the torso during a rapid stop of the vehicle.

To restrain the lower torso of the occupant within the seat during rapiddeceleration, the lap belts are provided with non-load limiting dynamicpretensioner retractors 44. These are operative upon initial sensing ofa rapid deceleration to apply increased tension on the lap belt andresultant restraint on the pelvic regions of the occupant by drawing theouter edges of the lap belt down to tension it tightly across the pelvicregions of the body and prevent the occupant's torso from sliding underthe lap belt during the deceleration occurrence. Such anti-submariningaction is aided by the shape and location of the anti-submarining ramp36 at the forward portion of the seat cushion 22. The upward slope oframp 36 causes the seat portion of the occupant's body to be supportedagainst the ramp while the lap belt tensions with a substantial force onthe pelvic region, thus restraining the lower portion of the body inposition in the seat and preventing the body from sliding underneath thelap belt. This provides an important function by controlling theoccupant's kinematics within the vehicle seat during a rapiddeceleration.

Some of the functions described may, of course, be provided by suitablealternative devices in place of the particular devices of the describedembodiments. However, it is presently considered that use of allfeatures of the invention or their equivalents is necessary to thesatisfactory operation of the apparatus in its broadest sense as hereindescribed and claimed.

While the invention has been described by reference to certain preferredembodiments, it should be understood that numerous changes could be madewithin the spirit and scope of the inventive concepts described.Accordingly, it is intended that the invention not be limited to thedisclosed embodiments, but that it have the full scope permitted by thelanguage of the following claims.

What is claimed is:
 1. Apparatus for restraining an occupant in anautomotive vehicle seat, said apparatus comprising: a seat having acushion mountable on a vehicle underbody and a seat back connected withthe cushion, the seat including a ramp sloping upward toward a forwardedge of the cushion; a pair of flexible lap belts connected at laterallyopposite sides of the seat and having inner ends transverselyconnectable to one another across pelvic regions of the occupant, thelap belts connected with at least one dynamic pretensioner; a pair offlexible shoulder belts connected to a support through at least one loadlimiting retractor and adapted, when in use, to extend in parallelrelation forward of the seat back, passing closely adjacent the neckportion and across the clavicle of the occupant from points not belowthe level of the clavicle, and to extend, essentially parallel, downwardacross front edge portions of the occupant's rib cage to laterallyspaced attachment with said lap belts; and adjustable guides on the seatback for guiding the shoulder belts to limit downward force on theclavicle prior to an occurrence of rapid vehicle deceleration. 2.Apparatus as in claim 1 wherein said adjustable guides in the seat backare disposed in an upwardly adjustable load-carrying headrest. 3.Apparatus as in claim 1 wherein said at least one load-limitingretractor is effective to allow controlled extension of the shoulderbelts upon reaching of a predetermined deceleration load.
 4. Apparatusas in claim 1 wherein said at least one load limiting retractorcomprises laterally spaced dual load limiting retractors connecting saidshoulder belts to said support.
 5. Apparatus as in claim 1 wherein saidat least one dynamic pretensioner comprises dual pretension retractorsmounted at laterally opposite sides of the seat.
 6. Apparatus as inclaim 1 wherein: the ramp prevents sliding of an occupant forward underthe lap belts during rapid slowing of the vehicle; said at least oneload-limiting retractor is effective to allow controlled extension ofthe shoulder belts upon reaching of a predetermined deceleration load;and said at least one dynamic pretensioner is effective to providedynamic pre tensioning of the lap belts upon reaching of a predetermineddeceleration value.
 7. Apparatus as in claim 6 wherein: said adjustableguides on the seat back are disposed in an upwardly adjustable loadcarrying headrest having rollers for guiding the shoulder belts over theclavicle of an occupant.
 8. Apparatus as in claim 7 wherein: saidshoulder belts are connected to said support through laterally-spaceddual load-limiting retractors; and said lap belts are connected to thecushion through dual pretension retractors mounted on structural seatadjusters at said laterally opposite sides of the seat.
 9. Apparatus asdefined in claim 1 wherein said essentially parallel spacing of theshoulder belts is adapted to be maintained at an essentially constantspacing of about 62.5 mm lateral offset in opposite directions from acenter of an intended position of the occupant and over a distance fromthe clavicle of the occupant to laterally spaced attachment to the lapbelts adjacent pelvic regions of the occupant.